Marine Mammals Taxonomy, Biogeography, and Evolution PDF

Taxonomy, Biogeography, and Evolution of Marine Mammals By: Dr. Maria Cartolano University of Miami ©  Class Mammalia Hair Sweat/mammary glands Homeothermic Four chambered...

Taxonomy, Biogeography, and Evolution of Marine Mammals By: Dr. Maria Cartolano University of Miami ©  Class Mammalia Hair Sweat/mammary glands Homeothermic Four chambered endotherms heart Three bones in inner ear Placenta Unique teeth Neocortex Three Marine Mammal Taxonomic Groups Order/Infraorder Cetacea Whales, dolphins, and porpoises Order Sirenia Manatees and dugongs Order Carnivora Pinnipeds = seals, sea lions, and walruses Marine fissipeds = polar bears and sea otters  Evolution: Moving from land to water Low light conditions Rely on oxygen in air Increased loss of heat through integument Increased density and viscosity Altered characteristics of sound propagation  Eart h’s hist ory. It is b roken up int o sect ions b ased on major event s, like in a new ep och: t he Ant hrop ocene. g lob al climate chang es and mass e xt inct ions. Use t his infog rap hic t o exp lore t he evolut ion of Eart h and t he lif e up on it. Ext inct Mass Ext inct ion e vent Holocene Pleist ocene 300,000 years ag o: The first “mod ern” human—Homo sap iens—evolves in Africa. Evolution Timeline Pliocene CENOZOIC 6.5 million years ag o: Hominins—early ancest ors of Miocene humans—evolve from t he ot her p rimat es. Olig ocene Eocene 60 million years ag o: The first p rimat es ap p ear. Paleocene 65.5 m ilio n years ag o Began in the Eocene Cret aceous 130 million years ag o: The first flowering p lant s evolve. MESOZOIC 56 to 34 million years ago Jurassic 150 million years ag o: Archaeop t eryx, “t he first b ird ,” lives in Europ e. Period of warming 200 million years ag o: The first mammals ap p ear. Triassic 250 million years ag o: Dinosaurs evolve and b eg in t o d ominat e Eart h. 252.2 m illio n years ag o Allowed for great opportunity for Permian 310 million years ag o: The four-leg g ed animals, not includ ing amp hib ians, sp lit int o t wo g roup s— rep t iles and “mammal-like” rep t iles. Mammals event ually evolve from t he second g roup. Carb oniferous 340 million years ag o: The first amp hib ians d evelop. expansion PALEOZOIC 397 million years ag o: The first animals wit h f our leg s (t et rap od s) evolve. This is Devonian t he common ancest or of all creat ures wit h t wo or four leg s, includ ing humans. During this time – mammalian groups Silurian Ord ovician 500 million years ag o: Plant s b eg in t o colonize land. 535 million years ag o: Many d ifferent t yp es of org anisms evolve in a relat ively short p eriod of began to appear and spread rapidly Camb rian t ime (a few million years) called t he Camb rian Exp losion. During t his “ exp losion” t he first t rue vert eb rate (animal wit h a b ackb one) ap p ear s. 541 m illio n years ag o Neo-p rot erozoic 139 modern species → not taxonomically PROTEROZOIC 2 b illion years ag o: First evid ence of eukaryot ic cells—cells t hat cont ain int ernal Meso-p rot erozoic “org ans” (org anelles), includ ing a DNA -cont aining nucleus. Recent d iscoveries diverse sug g est mult icellular lif e may have also d evelop ed d uring t his t ime. 2.4 b illion years ag o: Eart h’s at mosp here fills wit h o xyg en. A million years Paleo-p rot erozoic lat er Eart h freezes over, creat ing t he first “Snowb all Eart h.” 2.5 b illio n years ag o Neo-archean ARCHEAN Meso-archean Paleo-archean Eo-archean 3.5 b illion years ag o: First evid ence of sing le -celled org anisms. 4 b illio n years ag o HADEAN 4.6 b illion years ag o: Eart h is formed. The moon forms ab out 100 million y ears aft erward s.  Taxonomy and Systematics Concepts Fossil record is very important in Zhou et al., 2015 understanding marine mammal evolution Systematics (distribution, gross and fine morphology, molecular ID, behavior) blue = maxilla Phylogeny green = frontal Morphological vs. molecular orange = occipital yellow = nasal Roston and Roth, 2019  Shared Marine Mammal Features Live part or all their life in water Rely on marine habitats for food Similar anatomical features: large body size, streamlined shape, insulation, decrease in presence and size of appendages Similar physiological adaptations to thrive in aquatic environment Most/many are, or have historically been, deliberately exploited and decimated by incidental takes and habitat destruction/modification  Three Taxonomic Groups 1. Order Cetartiodactyla Suborder Whippomorpha (includes hippos) Domain Infraorder Cetacea Kingdom Parvorder Mysticetes – baleen whales Parvorder Odontocetes – toothed whales Phylum 2. Order Sirenia Class Family Trichechidae - manatees Family Dugongidae - dugongs Order 3. Order Carnivora Suborder Caniformia Family Infraorder Arctoidea Genus Superfamily Pinnipedia – seals, sea lions, walrus Superfamily Ursoidea – polar bears Species Superfamily Musteloidea – sea otters  Marine Mammal Species 1. Order Cetartiodactyla Current List of All Marine Infraorder Cetacea (94 species; 1 possibly extinct) Mammal Species and Suborder Mysticetes – baleen whales (15 species) Subspecies from Society Suborder Odontocetes – toothed whales (79 species) of Marine Mammology 2. Order Sirenia (5 species) 139 Total Species Family Trichechidae – manatees (3 species) (4-5 extinct) Family Dugongidae – dugongs (2 species; 1 extinct) 3. Order Carnivora Infraorder Arctoidea Superfamily Pinnipedia – seals, sea lions, walrus (36 species; 2 extinct) Superfamily Ursoidea – polar bears (1 species) Superfamily Musteloidea – sea otters (3 species; 1 extinct)  Species Names in Scientific Writing When you first introduce a species, make sure to: *If you aren’t sure on capitalizations, check NOAA or Society for Marine Mammalogy 1. Spell out the complete common name (e.g., West Indian manatee; common bottlenose dolphin). 2. Only capitalize the first letter(s) of a common name IF it is: The first word in a sentence Rough-toothed dolphins can be found in warmer waters around the world. Related to a location Satellite tags were attached to three North Atlantic right whales. A person’s name The main threats affecting Rice’s whales are noise, oil spills, vessels, and entanglement. 3. Following the common name, include the scientific name in parenthesis and italics Common prey types of Atlantic spotted dolphins (Stenella frontalis) are fish, squid, and invertebrates. After introducing the species, the first time, then you can refer to them with common or scientific name: Atlantic spotted dolphins, spotted dolphins, dolphins, Stenella frontalis, S. frontalis  Biogeography Physical Drivers: temperature and coastal shelves Directly or indirectly affect range Often species have distinct latitudinal bands Usually found in one hemisphere; less commonly both Migratory, small ranges, or cosmopolitan Still very little known about ranges of many species  Cetaceans Shared Characteristics: Spend entire lives in water → extreme adaptations Breathe through nostrils on top of head Increased breath hold capacity Thick blubber Large size Vascular heat exchange system Smooth skin Reduction of appendages Broad, horizontal tail flukes Dorsal fin Some (odontocetes) have advanced sound processing capabilities  Cetacean Evolution Historically, whales were considered fish not mammals Relationship to artiodactyls/even-toed ungulates accepted with most evidence pointing to hippos as closest relative Ungulates – even-toed (pigs, cows, camels, hippos) and odd-toed (horses, tapirs, and rhinos) Even-toed – chambered stomach to digest tough plant material (odd-toed digest this in intestines) Ungulates regurgitate their food – hippos and cetaceans do not  Cetacean Evolution Hippos and Cetaceans: Split from animals that eventually became modern day ruminants (even-toed ungulates) “Whippo” concept emerged (i.e., common ancestor and closest surviving relative) Similarities include: Whale flipper and hippo foot Chambered stomachs/no regurgitation Non-lobed lungs Underwater behavior – nursing young, signaling, clicking and fatty structure in jaw Few hairs and no sweat glands Blubber Thick bones – helps with buoyancy Baby Hippo Hippos walk, not swim Sample spectrograms of hippo (1) a broadband click train and (2) a narrowband click train while searching for carrots underwater (Maust-Mohl et al., 2019).  Cetacean Evolution 1. Archaeoceti (extinct) Gave rise to modern cetaceans Tidal and estuarine habitats Looked reptilian Ambulocetus = walking whale From this to fully aquatic: Shift from 4-legged locomotion to swimming Ability to drink seawater Basilosaurus = “king lizard” Ability to give birth in water Whale Evolution  Cetacean Evolution 2. Odontoceti Have teeth (ancestral) Possess 5 digits in pectoral flippers Notable changes: Asymmetric skulls 1 nostril Echolocation Directional hearing  Cetacean Evolution 3. Mysticeti Earliest fossils had teeth, then had both, then just baleen 2 nostrils Possess only 4 digits in pectoral flipper (excluding right whales) Killer Sperm Right Humpback whale whale whale Cooper et al., 2007  Cetaceans Mysticetes 4 families 15 species Characteristics: Size range: pygmy right whale (6 m) to blue whale (30 m) Sexual dimorphism - females larger Two blowholes Filter feeders - gulpers vs. skimmers (plankton) Teeth replaced by baleen - triangular plates of fibers (keratin) Diameter depends on diet Passive feeders - less developed musculature Mysticete Families 1. Family Balaenopteridae (rorqual whales) 9 species 1. Blue whale Northern, Antarctic, Blue Northern Indian Ocean, Pygmy 2. Fin whale Fin North Atlantic, Southern, North Pacific 3. Sei whale Sei Northern, Southern 4. Byrde’s whale Bryde’s Byrde’s, Eden’s Omura’s 5. Omura’s whale 6. Rice’s whale Bryde’s 7. Common minke whale Antarctic North Atlantic, North Pacific Minke 8. Antarctic minke whale Common Minke 9. Humpback whale Southern, North Pacific, North Atlantic Mysticete Families 1. Family Balaenopteridae (rorqual whales) Characteristics: Sleek - “greyhounds of the sea” Dorsal fin: inversely proportional to size Long, distinct ventral grooves/throat pleats Baleen short and wide Huge tongues Biogeography: Predominantly migratory (some species further than any other mammal) Rice’s whale Food, energy, mating, calving, nursing Many cosmopolitan Mysticete Families 1. Family Balaenopteridae (rorqual whales) 9 species – how to tell them apart! 1. Blue whale (Balaenoptera musculus) Largest extant animal – up to 110 feet. (33 m) Mottled blue-gray color Tall blow pattern (6-9 m) Small dorsal fin Blow hole looks like a bump at surface Cosmopolitan range Mysticete Families 1. Family Balaenopteridae (rorqual whales) 2. Fin whale (Balaenoptera physalus) Sometimes also called finback Second largest whale Black or dark brown/gray on heads and side; white ventral side Asymmetric head coloring: Right jaw = light Left jaw = dark Light gray chevrons behind head Tall thin blow pattern (6 m) Cosmopolitan range Mysticete Families 1. Family Balaenopteridae (rorqual whales) 3. Sei whale (Balaenoptera borealis) Dark bluish-gray to black in color and white/cream on underside; sometimes subtle mottling Smaller than fin whales (3 rd biggest) Often covered in oval-shaped scars (from cookie-cutter shark and lamprey bites) Columnar or bushy blow (3-4m) Sink rather than arch backs to dive Cosmopolitan range Sei Whale Feeding Mysticete Families 1. Family Balaenopteridae (rorqual whales) 4. Bryde’s whale (Balaenoptera edeni) Pronounced "broodus” Prefer warmer waters 3 prominent ridges in front of blowhole Eden’s subspecies – Indian and Western Pacific (coastal) Bryde’s subspecies - larger, pelagic waters Mysticete Families 1. Family Balaenopteridae (rorqual whales) 5. Omura’s whale (Balaenoptera omurai) First described as pygmy form of Bryde’s whale, now considered different species Also called dwarf fin whale Second smallest of all rorquals Like fin whale: asymmetric head coloring: Right jaw = light Left jaw = dark Single prominent ridge on rostrum Mysticete Families 1. Family Balaenopteridae (rorqual whales) 6. Rice’s whale (Balaenoptera ricei) First called Gulf of Mexico Brdye’s whale Discovered as new species in 2021 Only resident baleen whale in Gulf of Mexico 3 prominent ridges in front of their blowhole (like Bryde’s whales) Uniformly dark gray on top with a pale to pink belly Mysticete Families 1. Family Balaenopteridae (rorqual whales) 7. Common minke whale (Balaenoptera acutorostrata) 8. Antarctic minke whale Black to dark gray/brown body (Balaenoptera bonaerensis) Pale chevron behind head and White patch is absent on flippers – above flippers, white ventral instead are solid gray with white Distinguished by small size leading edge (smallest rorqual whale) Southern hemisphere White patch/band on pectoral flipper Mostly northern hemisphere Common minke Antarctic minke Mysticete Families 1. Family Balaenopteridae (rorqual whales) 9. Humpback whale (Megaptera novaeangliae) Primarily black with different amounts of white on fins, flippers, ventral flukes Bumps = tubercles Large pectoral flippers Shorter bushy blow, 3-4m high Cosmopolitan range - 14 distinct population segments (DPS) Humpback Whales Mysticete Families 2. Family Balaenidae Bowhead whale 4 species 1. Bowhead whale (Balaena mysticetus) 2. North Atlantic right whale (NARW) (Eubalaena glacialis) North Atlantic right whale 3. Southern right whale (Eubalaena australis) 4. North Pacific right whale (Eubalaena japonica) Southern right whale North Pacific right whale Bowhead whale Mysticete Families 2. Family Balaenidae Characteristics: Large, dark, huge mouths No dorsal fin No throat grooves (true filter feeders) orange white Baleen is longest of all mysticetes Right whales: Callosities on 3 right whale species (not bowheads) V-shaped blow Mysticete Families 2. Family Balaenidae Biogeography: Bowhead whale - only baleen whale found in arctic and subarctic Southern and northern right whales – in each hemisphere  Bowhead whales Southern right whales North Atlantic right whales Mysticete Families 3. Family Neobalaenidae 1 species Pygmy right whale (Caparea marginate) Characteristics: Smaller and sleeker, similar head/mouth shape, and lighter in color compared to other right whales Falcate dorsal fin Confused with minke https://www.youtube.com/watch?v=e4Zf9ROiz1g “Data deficient” (IUCN) Biogeography: Distinct latitudinal band in southern hemisphere Mysticete Families 4. Family Eschrichtiidae 1 species Gray whale (Eschirichtius robustus) Characteristics: Atlantic and Korean species – extinct 2-5 throat grooves Small dorsal fin followed by ridges/knuckles Unique bottom feeding Give birth in lagoons Almost hunted to extinction in 1850s Recent studies indicate similarity to humpbacks and fin whale Long migrations Mysticete Families 4. Family Eschrichtiidae 1 species Gray whale (Eschirichtius robustus) Biogeography: North Pacific Shelf waters but highly migratory Went extinct from Atlantic by 1700s A few whales found in other places – recently 1 seen off coast of Miami!  Cetaceans Odontocetes 10 families 79 species (1 possibly extinct) Characteristics: Toothed whales, dolphins (including river dolphins), and porpoises Size range – vaquita/Hector’s dolphin (1.5 m) to sperm whale males (15 m) All have teeth but not erupted in some Most are homodonts Echolocation Single blowhole Sexual dimorphism – males larger Biogeography: Great variation Odontocete Families 1. Family Physeteridae 1 species Sperm whale (Physeter macrocephalus) Characteristics: Extreme sexual dimorphism Deep divers (2000+ m/90+ min. breath hold) Short/squat dorsal followed by ridges Huge head - spermaceti organ Blow pattern projects forward Biogeography: Deep water, wide latitudinal range Odontocete Families 2. Family Kogiidae 2 species Dwarf sperm whale (Kogia sima) Pygmy sperm whale (Kogia breviceps) Characteristics Smaller (2.7 m and 3.1 m respectively) Short heads, similar appearance, different proportions K. breviceps Spermaceti organ Ink Biogeography: Found in temperate, sub-tropical, and tropical waters K. sima Odontocete Families 3. Family Monodontidae 2 species Beluga, white whale (Delphinapterus leucas) Narwhal (Monodon monoceros) Characteristics No dorsal fin Narluga hybrid Biogeography: Found in the Arctic Pagophilic, discontinuous circumpolar distribution Skrovind et al., 2019 (not real pic) Odontocete Families 3. Family Monodontidae Characteristics Beluga All white color Peg-like teeth Flexible head “Sea canary” Narwhal Males - long, spiraling tusk (tooth) Sensory function and sexual selection Narwhals Belugas Odontocete Families 4. Family Ziphiidae (beaked whales) 6 genera 24 species Characteristics Deep divers (record 2,992 m) Cuvier’s Blainville's Sensitive to sonar activities Small – medium size with narrow rostrum 2-4 teeth that usually erupt in males Rake marks are signs of aggression Blainville’s Female Strapped- Blainville's toothed Male Odontocete Families 4. Family Ziphiidae (beaked whales) 24 species 1. Arnoux’s beaked whale 14. Hector’s beaked whale 2. Baird’s beaked whale 15. Deraniyagala’s beaked whale 3. Sato’s beaked whale 16. Strap-toothed beaked whale, 4. Northern bottlenose whale Layard’s beaked whale 5. Southern bottlenose whale 17. True’s beaked whale 6. Longman’s beaked whale, 18. Perrin’s beaked whale tropical bottlenose whale 19. Pygmy beaked whale 7. Sowerby’s beaked whale 20. Stejneger’s beaked whale 8. Andrews’ beaked whale 21. Spade-toothed whale 9. Hubbs’ beaked whale 22. Blainville’s beaked whale 10. Ramari’s beaked whale 23. Shepherd’s beaked whale, 11. Gervais’ beaked whale Tasman beaked whale 12. Ginkgo-toothed beaked whale 24. Cuvier’s beaked whale, 13. Gray’s beaked whale goose-beaked whale Odontocete Families 4. Family Ziphiidae (beaked whales) Biogeography: Deep water, very cryptic Cuvier’s Beaked Whale Gervais' Beaked Whale Odontocete Families Risso’s 5. Family Delphinidae 17 genera 38 species Characteristics: Irrawaddy Largest and most diverse group Size range: Hector’s (1.2 m) to killer whale (9 m) “Blackfish” - 6 similar species Killer whale, false killer whale, pygmy killer whale, 2 pilot whales, melon- headed whale Southern right whale dolphin Northern right whale dolphin Dark color, decreased dentition, no beak Rest share typical “dolphin” shape: distinct beak, prominent dorsal, 20+ pairs of teeth Odontocete Families 5. Family Delphinidae 38 species 1. Commerson’s dolphin 12. White-beaked dolphin 27. Australian humpback dolphin Commerson’s, Kerguelen 13. Peale’s dolphin 28. Tucuxi 2. Chilean dolphin 14. Hourglass dolphin 29. Guiana dolphin, costero 3. Heaviside’s dolphin 15. Pacific white-sided dolphin 30. Pantropical spotted dolphin 4. Hector’s dolphin 16. Dusky dolphin Offshore, coastal South Island, Māui/North Fitzroy’s, African, Peruvian/Chilean 31. Clymene dolphin Island 17. Northern right-whale dolphin 32. Striped dolphin 5. Common dolphin 18. Southern right-whale dolphin 33. Atlantic spotted dolphin Common, Eastern North Pacific 19. Irrawaddy dolphin, pesut 34. Spinner dolphin long-beaked, Black Sea, Indo- 20. Australian snubfin dolphin Central American, Gray’s, Eastern, Pacific 21. Killer whale, orca Dwarf 6. Pygmy killer whale Common, Bigg’s, Resident 35. Rough-toothed dolphin 7. Short-finned pilot whale 22. Melon-headed whale 36. Indo-Pacific bottlenose dolphin 8. Long-finned pilot whale 23. False killer whale 37. Tamanend’s bottlenose dolphin Southern, North Atlantic 24. Atlantic humpback dolphin 38. Common bottlenose dolphin 9. Risso’s dolphin, grampus 25. Indo-Pacific humpback dolphin Black Sea, Common, Lahille’s, 10. Fraser’s dolphin Chinese, Taiwanese Eastern Tropical Pacific 11. Atlantic white-sided dolphin 26. Indian Ocean humpback dolphin  Tursiops truncatus and Tursiops erebennus Common bottlenose dolphin (Tursiops truncatus) found around the world 61 stocks; 4 subspecies; none listed under ESA In western North Atlantic, there are two ecotypes (coastal and offshore) New study determined that they are two distinct species using traditional and geometric morphometrics as well as mitochondrial and nuclear DNA Newly named coastal species Tursiops erebennus (for darker coloration) Common name: Tamanend’s bottlenose dolphin (Chief Tamanend from Turtle Clan of Nanticoke Lenni-Lenape Tribal nation) Killer whales (Orcinus orca) – 1 species; 3 subspecies A 2024 study that suggested that eastern North Pacific Bigg’s killer whales should be recognized as Orcinus rectipinnus and resident killer whales should be recognized as Orcinus ater. Society for Mammalogy ruled against this in July 2024, but now recognizes them as subspecies. Odontocete Families 5. Family Delphinidae Anti-tropical = Biogeography: not found in red Deep, warm water - spinner, common, rough-toothed dolphins Anti-tropical, offshore - Pacific white sided, dusky dolphins Coastal - humpback dolphins, Irrawaddy, bottlenose dolphins Estuaries/bays/sounds – Irrawaddy dolphin Bottlenose dolphins Freshwater tolerant – Guiana, Tucuxi Temperate and tropical, coastal and offshore, + variety of habitats – bottlenose dolphin Cosmopolitan – killer whale Odontocete Families 6. Family Phocoenidae (porpoises) 7 species 1. Indo-Pacific finless porpoise 2. Narrow-ridged finless porpoise Yangtze, East Asian 3. Spectacled porpoise 4. Harbor porpoise Atlantic, Pacific, Black Sea 5. Vaquita 6. Burmeister’s porpoise 7. Dall’s porpoise dalli-type, truei-type Characteristics: Vaquita Harbor porpoise Small and lacking beak Spatulate/flat teeth Small dorsal or no dorsal fin (2 finless porpoise) Odontocete Families 6. Family Phocoenidae (porpoises) Biogeography: Most are inshore, covering most of world’s coastlines Vaquita porpoise – northern Gulf of California Vaquita (P. sinus) Dark blue – harbor porpoise Light blue – Burmeister’s porpoise Yellow – Dall’s porpoise Red – spectacled porpoise Green – Indo-Pacific and narrow-ridged finless porpoises Odontocete Families Families 7-10 = River Dolphins Characteristics All have long beak, flexible neck, large/spatulate flippers, reduced eyes Biogeography Occupy 5 of world’s largest tropical rivers and drainage systems South America and Asia Odontocete Families 7. Family Platanistidae (South Asian river dolphins) 2 species Ganges river dolphin, susu, shushuk Ganges (Platanista gangetica) Indus river dolphin, bhulan (Platanista minor) Characteristics Small eyes, no lenses, flat cornea Indus Small dorsal fins, long snouts with long, thin, teeth Biogeography Ganges = India, Nepal, Bangladesh Ganges Indus = Pakistan Indus Evolution Evolved separately than other 3 families of river dolphins Odontocete Families 8. Family Lipotidae 1 species (possibly extinct) Baiji, Yangtze river dolphin, Chinese river dolphin (Lipotes vexillifer) Characteristics Last sighting in the early 2000s Biogeography Yangtze river, eastern China Baiji Dolphin Odontocete Families 9. Family Iniidae 1 species Amazon river dolphin (Inia geoffrensis) Bolivian bufeo, common boto Characteristics Different dentition – conical teeth and molars Hairs on rostrum Gray to pink coloration Neck vertebrae not fused Small eyes but decent sight Current UME from droughts Biogeography Bolivia, Brazil, Colombia, Ecuador, Peru, Guyana, and Venezuela Subspecies Bolivian bufeo further south with smaller range Boto/Pink Amazon River Dolphin Odontocete Families 10. Family Pontoporiidae 1 species Franciscana, toninha, La Plata (Pontoporia blainvillei) Characteristics Longest beak to body size ratio (15%) Biogeography Coastal waters of the southwestern Atlantic of Brazil, Uruguay, and Argentina Only river dolphin that lives in ocean and saltwater estuaries Order Sirenia 2 families 5 species (1 extinct) Characteristics: Obligate water dwellers (extreme adaptation) Herbivorous Characteristics that differ from cetaceans: Paired nostrils; anterior on head Dense skeletal bones No echolocation/less sensitive hearing Dentition - mastication Moderate size (excluding Steller’s sea cow – 8 m/7000 lbs)  Order Sirenia Biogeography: All extant species tropical or subtropical Extinct Steller’s sea cow Polar/Commander Islands Dugongs - exclusively marine Seagrasses in Indo-West Pacific Sheltered warm waters (though can travel 100s of km) West Indian and African manatees Salt/brackish/freshwater Access to aquatic plants Coastal range: West Africa SE US to Brazil Amazonian manatee Confined to freshwater habitats  Sirenian Evolution Sirenians have a 50-mya fossil record Fossil record is taxonomically rich Closest land relative – elephants Share common ancestor (Tethytheria) Manatees have vestiges of pelvic girdle  Amazonian Sirenian Families 1. Family Trichechidae (manatees) 3 species 1. Amazonian manatee (Trichechus inunguis) 2. West Indian manatee (Trichechus manatus) West Indian Florida manatee (T. m. latirostris) Antillean manatee (T. m. manatus ) 3. West African manatee (Trichechus senegalensis) Characteristics: Slow moving Fluke/paddle West African Warm water Maneuverable forelimbs Marching molars, no tusks Have fingernails (West Indian and West African) Sirenian Families Dugong 2. Family Dugongidae (dugongs) 2 species Dugong (Dugong dugon) Steller’s sea cow (Hydrodamalis gigas) - extinct Characteristics: Dugong Obligate bottom feeders Flukes more dolphin-like More well-developed musculature Males have pair of tusks Female tusks don’t erupt Canines, premolars, and molars No fingernails Steller’s sea cow Antillean Manatee Walking Underwater Dugongs Stellar Sea Cow  Order Carnivora Suborder Caniformia Infraorder Arctoidea Superfamily Pinnipedia 3 Families 36 species (2 extinct) Superfamily Ursidae 1 species Superfamily Mustelidae 3 species (1 extinct)  Carnivora Evolution Arctoidea Under Caniformia but excludes Canidae Includes mustelids, racoons, skunks, ferrets, badgers, bears, pinnipeds Several groups taken on partial marine existence, but ALL must come back to land to give birth, except sea otter Doronina et al., 2015  Carnivora Evolution Theory 1* Theory 2 1. Pinnipeds Theory 1: phocids, odobenids, and otariids share direct common ancestor and that group shares an ancestor with bears* Theory 2: phocids more closely related to mustelids; otariids and odobenids more closely related to bears *Theory 1 is more agreed on Coastal upwelling areas → food attracted early pinnipeds to oceans 36 mya Fully flippered pinnipeds emerged 17 mya Modern species and walruses with tusks evolved more recently  Carnivora Evolution Arctoidea – includes most mustelids, racoons, bears, pinnipeds Several groups taken on partial marine existence, but ALL must come back to land to give birth, except sea otter 2. Polar Bears Recent evolution Evolutionary offshoot of the brown/grizzly bear Diverged from brown bear ~500,000 years ago Period of cooling and prevalence of ice sheets Adapted to life on ice and in water Flagship species – global warming ”pizzly” “grolar”  Carnivora Evolution 3. Sea Otters Also recent, evolving ~ 2 mya Evolved from Family Mustelidae (ferrets, weasels) 13 otter species Sea otters and marine otters can give birth on land and in water Pinniped Families Shared Characteristics: Amphibious lifestyle Modified hind limbs Most have dense fur Streamlined, fusiform body shape Anterior, double nostrils with sensory hairs Dentition - differentiated teeth Rely primarily on vision and touch Exceptional diving capabilities Moderate size (largest: elephant seal 4 m/5000 lbs) Pinniped Families Biogeography: Very abundant with global distribution Pinnipeds – higher latitudes than cetaceans Established year-round presence in ice zones (Arctic and Antarctic) Some persist in confined lake systems Haul out sites – critical Human interactions Pinniped Families 1. Family Odobenidae 1 species Walrus (Odobenus rosmarus) Atlantic, Pacific Characteristics: Long, external tusks (males and females) Sexual dimorphism Strong front flippers to pull itself Highly enervated muzzle Bottom feeders Thick, warty skin (~ 4 cm) Ample blubber (5-10 cm) Ear holes but no external ear Pinniped Families 1. Family Odobenidae 1 species Walrus (Odobenus rosmarus) Atlantic, Pacific Biogeography: Arctic distribution Circumpolar patchy distribution 2 subspecies – based on biogeography Atlantic, Pacific, (Russian/Laptev debated) Limited to shallow water – benthic prey Can aggregate in large groups - herd  California sea lion Pinniped Families 2. Family Otariidae (eared fur seals and sea lions) 16 species (1 extinct) Characteristics: External ear flaps (pinnae) South American sea lion Long, hairless flippers with splayed digits and vestigial nails Rotatable pelvic bone and hind flippers - “walk” on land Use fore flippers to propel themselves through water Thick undercoat (fur) not present among “true seals” Pronounced sexual dimorphism and polygynous Social and gather in groups Very vocal Northern fur seal Fur seals Morphologically similar Geographically distinct South American fur seal Pinniped Families 2. Family Otariidae (eared fur seals and sea lions) 16 species (1 extinct) Characteristics: Fur seals (compared to sea lions): Thicker fur coat Smaller in size More pronounced sexual dimorphism Shorter nose with eyes closer to nose Ear flaps larger and stick out farther from head Proportionally longer flippers Pinniped Families 2. Family Otariidae (eared seals and sea lions) 16 species (1 extinct) Fur Seals Sea Lions 1. South American fur seal 1. Steller sea lion, northern sea lion 2. Long-nosed fur seal, New Zealand fur seal Western, Loughlin’s 3. Galapagos fur seal 2. Australian sea lion 4. Antarctic fur seal 3. South American sea lion 5. Juan Fernandez fur seal 4. New Zealand sea lion, Hooker’s sea lion 6. Guadalupe fur seal 5. California sea lion 7. Cape fur seal 6. Galapagos sea lion Cape, Australian 7. Japanese sea lion – 8. Subantarctic fur seal extinct 9. Northern fur seal Pinniped Families 2. Family Otariidae (eared seals and sea lions) Biogeography: Fur seals Global but concentrated 8 species – non-overlapping distribution Only 2 species in northern hemisphere - northern fur seal & Guadalupe fur seal (subspecies of Juan Fernandez) Northern fur seal South American fur seal Pinniped Families 2. Family Otariidae (eared seals and sea lions) Biogeography: Sea lions Wider range than phocids, less prominent in poles Steller sea lion – eastern & western (endangered) Zalophus species: Zalophus wollebaeki Zalophus californianus Zalophus japonicus (extinct) Northern fur seal California sea lion Pinniped Families Hawaiian monk seal 3. Family Phocidae (earless or true seals) 13 genera 19 species (1 extinct) Ringed seal Characteristics: Weddell seal Harbor seal Lack pinnae, has ear holes Shorter, haired forelimbs Moves like an inchworm on land Non-rotatable hind limbs Moves hind flippers back and forth to propel themselves in water Less vocal Northern elephant seal Less pronounced sexual dimorphism Highly diverse color patterns Many species are more solitary Leopard seal Pinniped Families 3. Family Phocidae (earless or true seals) 19 species (1 extinct) 1. Hooded seal 12.Hawaiian monk seal 2. Bearded seal 13.Ross seal Atlantic, Pacific 14.Harp seal 3. Gray seal 15.Harbor seal, common seal Baltic, Atlantic Atlantic, Ungava, Pacific 4. Ribbon seal 16.Spotted seal, largha seal 5. Leopard seal 17.Ringed seal 6. Weddell seal Arctic, Baltic, Okhotsk, 7. Crabeater seal Lake Ladoga, Saima 8. Southern elephant seal 18.Caspian seal 9. Northern elephant seal 19.Baikal seal 10.Mediterranean monk seal 11.Caribbean monk seal, West Indian monk seal – extinct Pinniped Families 3. Family Phocidae (earless or true seals) 19 species (1 extinct) 1 possible new seal species in 2023! Kangia ringed seal Distinct from other Arctic ringed seals Local Inuit communities in Greenland and Canada recognized several regional variants leading to scientific studies to show it has been genetically isolated for > 100,000 years Pinniped Families 3. Family Phocidae (earless or true seals) Biogeography: True seals Many species haul out and breed on ice (both poles) Southern and northern groups/species Seals in warmer waters haul out on rocky shores, cold waters on ice Freshwater lake seals - Baikal seal Hawaiian monk seal and extinct Caribbean monk seal – only warm water pinnipeds Many species exhibit long migrations – breeding/feeding grounds Northern elephant seals – males travel farther (more energy reserves) → habitat partitioning Baikal seal Elephant Seals Hooded Seals Leopard Seal Baikal Seal Superfamily Ursidae 1. Ursidae (bears and pandas) 1 marine mammal species Polar bear (Ursus maritimus) Characteristics: Least adapted to aquatic lifestyle Hollow, transparent hair (buoyancy) Streamlined compared to terrestrial bears (no should hump, small ears and head, long neck) Long, sustained swimming Long legs and large webbed paws with non- retractable claws Eyes - nictitating membrane Largest land carnivore Specialist predator of seals Superfamily Ursidae Polar bear (Ursus maritimus) Biogeography: Distribution mirrors northern phocid seals (primarily ringed seals) Live in close association with ice packs - depend on ice Male polar bears are true nomads Grolar Bear Polar Bear Swimming  Sea otter Superfamily Mustelidae 1. Mustelidae (minks, badgers, weasels, wolverines, otters) 3 marine mammal species (1 extinct) Sea otter (Enhydra lutris) Eastern, Western, Southern subspecies Marine Otter Chungungo, marine otter (Lontra felina) Sea mink (Neovison macrodon) - extinct Characteristics: Extremely dense fur Amphibious lifestyle (spend a lot of time floating) Skin flap for food storage Sea mink Use tools (crustaceans and mollusks) Horizontally flattened tail & flattened hind feet Large, up to 5 ft. (giant river otter is longest; sea otter heaviest) Eat benthic molluscs and crustaceans - can dive over 300 ft deep Keystone species Superfamily Mustelidae Biogeography: Sea otter (Enhydra lutris) Japan to Aleutian Islands; down California coast Fragmented (exploitation); reintroduction Marine otter (Lontra felina) South America Coastal (most consume benthic invertebrates)  List of Proposed, Un-named Marine Mammal Species and Subspecies Subspecies removed from the 2019 list: Peruvian fur seal Dwarf minke whale Chilean blue whale North Pacific long-finned pilot whale – extinct New Zealand dusky dolphin Eastern North Pacific resident killer whale Eastern North Pacific transient killer whale, Bigg’s killer whale Western Pacific harbor porpoise Afro-Iberian harbor porpoise  Marine Mammal Taxonomy Practice Optional practice to use as study guide Fill in the text boxes with information to help you remember the different marine mammal groups with very brief information about the characteristics You should also be able to recognize names of species that fit into each group  CREATURE FEATURE ASSIGNMENT! On Canvas, submit a list of THREE marine mammal species that you never heard of or know very little about - due Aug. 29 You will be assigned one species to do a creature feature slide and add it to this Google Slides presentation – due Sept. 10 Starting on Sept. 12, one-two people will present their creature feature slide at the beginning of class